Supported ionic liquid phase (SILP) facilitated gas-phase enzyme catalysis – CALB catalyzed transesterification of vinyl propionate†
The supported ionic liquid phase (SILP) technology has been used to immobilize Candida Antarctica Lipase B (CALB) within a hybrid monolith. The monolith was synthesized in situ inside a Teflon® cartridge via the 4-(dimethylamino)pyridine-catalyzed polyaddition of 1,1,1-tris(hydroxymethyl)propane to 4,4′-methylenebis(phenylisocyanate) in the presence of porous cellulose-2.5-acetate beads. An ionic liquid containing small amounts of CALB was impregnated into these beads and the resulting enzyme-SILP (e-SILP) catalyst was tested in the continuous gas-phase transesterification of vinyl propionate and 2-propanol. The enzyme was catalytically active with conversions exceeding 30% at short contact times of only 24 s. Total turn-over numbers of 1.7 × 108 and 2.4 × 108 molsubstrate molCALB−1 could be obtained for the two e-SILP cartridges tested. High stability could be achieved at relatively high reaction temperatures around 65 °C for more than 700 h time on stream.